Minicells, the spiky gold balls, emerge from the leaky blood vessel within the tumour mass. They proceed to disable the tumour cells with a one-two punch as shown in the enlarged tumour cell below. Following the arrows clockwise, the minicells first deliver siRNA to disable the MDR pump (small purple dumbbells). Then they deliver the cancer drugs (small red spheres).
Credit: Russell Kightley
MELBOURNE: Specially designed 'minicells' successfully target and kill cancer cells – the new technology has the "potential to deliver drugs that were considered undeliverable," scientists say.
In mice seeded with human tumours, then treated with this new technique, the recovery rate was 100%. In the next few months, EnGeneIc will recruit 20 long-term cancer patients for a phase one safety trial at three Melbourne hospitals.
The study, by Jennifer MacDiarmid and Himanshu Brahmbhatt of EnGeneIC, a privately held Australian bioscience company founded in 2001, is the cover story of the July issue of Nature Biotechnology.
Fighting drug-resistant cancer
One of the major problems in cancer treatment today is that the cancer often returns in a form that is resistant to treatment. But many drugs that are developed to fight cancer can not be used because they are too toxic or they are unstable in the blood stream.
Cancers evolve, just like organisms, and develop new genetic mutations that fight off the drugs used against them. In recent years the discovery of small interfering RNA (siRNA) has provided the means to beat cancer at its own game.
Small interfering RNA can neutralise whatever new genetic mutations the cancer develops. "The beauty of siRNA is that we can tailor the therapy to the tumour", says MacDiarmid.
The problem is that siRNA is unstable – it normally works within cells, and doesn't travel well via the bloodstream. Until now, doctors and scientists had no way of using siRNA to fight cancer in patients.
'Trojan horse' enters cancer cells
"Delivery, delivery, delivery has been the major problem", says MacDiarmid. EnGeneIC's solution was to develop a 'Trojan horse' that would seek and enter cancer cells and then disarm them using siRNA.
Their Trojan horse is made from the bacterium Salmonella typhimurium. MacDiarmid and Brahmbhatt genetically engineered bacteria so that they not only split in two they also budded off fragments at their ends.
These fragments, dubbed 'minicells', are ideally equipped to act as Trojan horses. For one thing their robust bacterial cell wall makes them capable of surviving the rough and tumble of a trip through the bloodstream.
They can also be fitted with a guidance system: molecules called lipopolysaccharides form part of their cell membranes, and these serve as attachment points for antibodies that target receptors on tumour cells.
Can this method be used on
Can this method be used on skin cancers such as melanoma? My mother has it, i was wondering if this can be used to treat it.
Colorectal Ca
Hi. Can this technology be used for Stage 4 Colorectal Ca? What is its side effect profile?
Antibody coated packages.
I worked on drug toxicology and cancer chemotherapy research at Melbourne Uni about 50 years ago.
I decided to leave the field when I realized that my organic synthesis skills were inadequate to make a combination of toxin and specific carrier molecule to provide a targeted attack on the tumor.
I realized that this required antibodies for specificity and that to train as an immunologist would take me too many years.
This present work is very heartening. Taylored to the individual physiology it might indeed result in cures on a case by case basis.
Mutated adult stem cells seem to be implicated in several tumors and "bombing" these and then replacing them may be an elegant cure.
However prevention of cancers is probably the most effective use of our energies.
It is now known that our modern diet and lifestyle cause most cancers, and if we choose to eat and live differently the results would be a great reduction in disease.
For example eating more fresh fruit and vegetables may reduce cancers by over 60% and load bearing exercise
In men has been shown to reduce cancer by 35-40%.
The essential problem is that our lifestyle is mismatched against the needs of our evolved bodies.
In summary "a cure for cancer" is probably not a realistic objective as the disease takes so many forms.
But we are certainly much better placed to prevent much unnecessary disease and to use beautiful techniques of the above "minicell" type to better treat cancer when it arises.
Congratulations and Best Wishes Ron Horgan
minicells
Killer Mini cells
Sir , It is indeed great to learn that new advancements are seen in field of Oncology.
Despite the fact of the recent progression in detection, therapy ,and maintenance of the disease is there any answer to cancer ?
Now the research says individuals of certain genetic traits are more prone to develop cancer and mark them as a high risk persons.
The radiation programmed and chemotherapy planned it selves are carcinogenic by nature . Certain therapies advised to day are contradicted tomorrow.
If extension of life span with worst possible side effects and exorbitant amounts involved is the outcome , it really compel to question ourselves “weather we are on the right path of fighting cancer”..
Talluri Vijai Kumar
Cancer
Can you please tell me the side effects for this.